Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
Poultry Science
Non Technical Summary
Problems: Skeletal problems in broilers are important economic issues for the broiler industry. Rapid muscle growth in broiler chicks (meat-type chicks) through genetic selection causes imbalance between meat production and skeletal growth. These skeletal problems in broilers cost the broiler industry over $300 million annually (Cook, 2000; Bell and Weaver, Jr., 2002). Another important issue is effective feed nutrient utilization. Since global feed cost increases every year, enhancing feed nutrient utilization is critical for the broiler industry. Excess body fat accumulation in broilers is an important economic issue for the broiler industry because broilers utilize much more nutrients and energy to produce fat tissues than to produce other body components (muscle and bone). If we limit nutrients for excess fat accumulation, more nutrients can be utilized for body maintenance and muscle/bone formation. Thus, developing innovative methods for healthy bone development, fat tissue reduction and effective nutrient re-partitioning could have a huge impact on efficient broiler production.Proposed research: Identifying bioactive molecules, which stimulate bone formation and reduce excess fat accumulation in broilers, will provide novel tools to enhance broiler health/growth and profits for the broiler industry. We believe that oxysterols could be promising bioactive molecules for the broiler industry. Previously, we have shown that specific oxysterols, 20S, 25, 22R, 22S, 34, and 49, increased osteoblasts (bone forming cells) and reduce adipocytes (fat forming cells) in in vitro cell cultures, and 20S, 34, and 49 oxysterols significantly enhanced bone formation in in vivo models. Thus, the objectives of the proposed study are 1) to determine the effects of in ovo injection of oxysterols on chick embryonic development, bone development, hatchability and chick quality; 2) to determine the effects of in ovo injection of selected oxysterols on growth performance, bone formation, body composition, and lipid and glucose metabolism in broilers; and 3) to determine the effects of dietary supplementation of selected oxysterols on growth performance, nutrient utilization, bone quality, fat reduction, lipid and glucose metabolism and carcass quality in broilers. We strongly believe that specific oxysterols can be potential bioactive molecules that can stimulate bone formation and reduce fat accumulation, improving broiler health, feed efficiency, and profits for the broiler industry. ?
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
a) To determine the effects of in ovo injection of oxysterols on chick embryonic development, bone development, body composition (bone, fat, & muscle), hatchability and chick quality.b) To determine the effects of in ovo injection of selected oxysterols on post-hatch growth performance, bone formation, body composition, and lipid and glucose metabolism in broilers.c) To determine the effects of dietary supplementation of selected oxysterols post-hatch on growth performance, nutrient utilization, bone quality, fat reduction, lipid and glucose metabolism, and carcass quality in broilers.
Project Methods
Procedures:Objective 1: To determine the effects of in ovo injection of oxysterols on chick embryonic development, bone development, body composition (bone, fat, & muscle), hatchability and chick quality.Experiment 1: This experiment is designed to screen effective in ovo injection dosages and potent bioactive oxysterols to stimulate embryonic growth and development. There are 6 bioactive oxysterols (20S, 25, 22R, 22S, 34, and 49) that demonstrated their pro-osteogenic and anti-adipogenic capability in MSC cultures (chicken and mouse) and in vivo animal models (rat/mouse). There will be four different dosage levels of these oxysterols: 5, 15, 50, and 100uM. At 0 d of incubation. A total of 280 fertile eggs will be divided into 7 groups (Control, 20S, 25, 22R, 22S, 34, and 49) with equal weight frequency distribution of 10 eggs per group (7 groups x 4 levels x 10 eggs/group). Each group will be injected with 1 mL of each treatment solution with a 21-gauge needle. After the eggs are injected, the holes will be sealed with cellophane tape, and eggs will be placed in incubation trays. Since limb development begins from 3 d of incubation, leg limbs will be collected at 4 d of incubation. Because oxysterols stimulate bone formation and inhibit fat formation by activating Hedgehog signaling (HH), which is the key signaling for embryonic and bone development, mRNA expression of HH key mediators (Gli and Patched) and key bone genes (Runx2: Master regulator of osteogenesis and osterix) will be measured from limb bud using Real-time PCR in order to screen effective dosages and potent oxysterols. Based on the result of the experiment 1, we will select three best oxysterols that stimulate HH signaling and key bone genes for experiment 2.Experiment 2: This experiment is designed to evaluate the effects of selected oxysterols on bone development, body composition (bone, fat, and muscle), hatchability and chick quality. There will be four treatments: 1) control, 2) oxysterol 1, 3) oxysterol 2, and 4) oxysterol 3. At 0 d of incubation, a total of 400 fertile eggs will be divided into 4 groups with equal weight frequency distribution of 100 eggs per group. Each group will be injected with 1 mL of each treatment solution with a 21-gauge needle.In this experiment, we will measure hatchability, chick weight, body composition and glucose and lipid related gene expression in liver and muscle on day 1 posthatch. Body composition will be measured by a dual energy X-ray absorptiometry (DEXA). The DEXA can measure fat %, lean muscle %, bone mineral density, and bone mineral contents.Experiment 3: This experiment is designed to evaluate the effects of oxysterol ovo injection time points on bone development, body composition, hatchability and chick quality. For this experiment, we will choose the best oxysterol from the data of the experiment 2. There will be five treatments: 1) control, 2) oxysterol at 0 d of incubation, 3) oxysterol at 4 d, 4) oxysterol at 10 d, and 5) oxysterol at 15 d. A total of 500 fertile eggs will be divided into 4 groups with equal weight frequency distribution of 100 eggs per group. Each group will be injected with 1 mL of each treatment solution with a 21-gauge needle.In this experiment, we will measure hatchability, chick weight, body composition and glucose and lipid related gene expression in liver and muscle. Body composition will be measured by a dual energy X-ray absorptiometry (DEXA). The DEXA can measure fat %, lean muscle %, bone mineral density, and bone mineral contents.Objective 2: To determine the effects of in ovo injection of selected oxysterols on growth performance, bone quality, body composition, and lipid and glucose metabolism in broilersExperiment 1: This experiment is designed to evaluate the effects of in ovo injection of selected oxysterols on growth performance, bone quality, fat reduction, and lipid and glucose metabolism of liver and muscle in broilers. There will be four treatments: 1) control, 2) oxysterol 1, 3) oxysterol 2, and 4) oxysterol 3. At 0 d of incubation, a total of 400 fertile eggs will be divided into 4 groups with equal weight frequency distribution of 100 eggs per group. Each group will be injected with 1 mL of each treatment solution with a 21-gauge needle. At hatch, the chicks from each treatment will be randomly assigned to 4 replicated floor pens (20 chicks per pen; 20ft2 pen). The birds will be fed three phase corn/soybean meal diets (starter for 0-2wk; grower for 2-4wk; finisher 4-6wk). Feed intake, body weight gain, and feed conversion ratio will be measured weekly. Body composition (lean meat%, fat%, moisture %, bone mineral density and bone mineral content) of live birds will be measured by a dual energy X-ray absorptiometry (DEXA). We can continuously monitor body composition changes of the same birds throughout the entire experiment period using DEXA. At 2 and 6 wk, left femur and tibia will be collected to measure bone breaking strength using an instron machine, and liver and jejunum samples will be collected for the gene expression of lipid and glucose metabolism ((Phophoenolpyruvate carboxykinase (PEPCK), Pyruvate Kinase (PK), Glucose Transporter 2 (GLUT2), Pyruvate Dehyrogenase (PDH)) Lipid metabolism (Acetyl-CoA acetyltransferase 2 (ACAT2), Peroxisome Proliferator Receptor-gamma (PPAR-gamma), Lipoprotein Lipase (LPL), Fatty acid synthase (FAS)) and intestinal nutrient transporters (Amino acid, glucose, and mineral transporters) using Real-Time PCR.Objective 3: To determine the effects of dietary supplementation of selected oxysterols on growth performance, nutrient utilization, bone quality, body composition, lipid and glucose metabolism, and carcass quality in broilersExperiment 1: This experiment is designed to evaluate the effects of dietary supplementation of selected oxysterols on growth performance, bone quality, fat reduction, and lipid and glucose metabolism of liver and muscle in broilers. There will be four treatments: 1) control, 2) oxysterol 1, 3) oxysterol 2, and 4) oxysterol 3. A total of 480 one day old chicks will be randomly assigned to 6 replicated floor pens (20 chicks per pen; 20ft2 pen). The birds will be fed three phase corn/soybean meal diets (starter for 0-2wk; grower for 2-4wk; finisher 4-6wk). Feed intake, body weight gain, and feed conversion ratio will be measured weekly. Body composition (lean meat%, fat%, moisture %, bone mineral density and bone mineral content) of live birds will be measured by a dual energy X-ray absorptiometry (DEXA). We can continuously monitor body composition changes of the same birds throughout the entire experiment period using DEXA. At 2 and 6 wk, left femur and tibia will be collected to measure bone breaking strength using an instron machine, and liver and jejunum samples will be collected for the gene expression of lipid and glucose metabolism ((Phophoenolpyruvate carboxykinase (PEPCK), Pyruvate Kinase (PK), Glucose Transporter 2 (GLUT2), Pyruvate Dehyrogenase (PDH)) Lipid metabolism (Acetyl-CoA acetyltransferase 2 (ACAT2), Peroxisome Proliferator Receptor-gamma (PPAR-gamma), Lipoprotein Lipase (LPL), Fatty acid synthase (FAS)) and intestinal nutrient transporters (Amino acid, glucose, and mineral transporters) using Real-Time PCR. At the end of the experiment, carcass quality will be evaluated using an industry standard procedure.Statistical analysisAll analyses of variance will be computed using SAS general linear models program software (SAS Institute, Cary, NC). Significant differences will be further separated using Tukey test and commercial statistical analysis software (SAS Institute, Cary, NC). All data will be analyzed by individual trial and statistical analyses considered significant at (P < 0.05)